But she said: "I bitterly, deeply regret that I didn't see it as more than individual cases that had gone wrong that needed addressing. I didn't see it as a systemic issue until very recently".

The row came amid deepening anger at the way members of the Windrush generation, who arrived from the Commonwealth in the decades following the Second World War and who have now been threatened with deportation, have been treated.

Ms Rudd told the Commons Home Affairs committee that so far 7,000 out of around 8,000 records dating back to 2002 had been checked with no wrongful removals discovered so far.

However, Rudd did not identity the so-called hostile environment immigration policy brought in when Theresa May was home secretary, which requires people to proactively prove their status, as a specific failing. But she echoed the Prime Minister, saying there was nothing wrong with trying to remove people who were in the country unlawfully.

Ms Rudd also rejected suggestions that the Tories' target to bring net migration below 100,000 had fuelled the Windrush saga.

Glynn Williams, the director general for border, immigration and citizenship, sitting beside her, said: "There are no published removal targets and there is nothing broken down by region, as far as I know".

Hours earlier Lucy Moreton, general secretary of the Immigration Service Union, was adamant there was a national deportations target - even broken down by region.

"Over the years, there have been individual cases of people who have had to regularise their documentation and have done so".

The Labour leader called for her successor Amber Rudd to resign for carrying on with the "cruel and misdirected" policy.

"But for governments of every colour, including that in which the Rt Hon Lady served, action has been taken against illegal immigrants".

The Windrush generation, named after one of the first ships that arrived from Jamaica in 1948, are citizens of the United Kingdom and colonies, a type of citizenship conferred by the British Nationality Act of 1948.

Persons who believe they fall within the category of the Windrush Generation or their children are being asked to use the British Home Office website and helpline to contact Jamaica's Ministry of Foreign Affairs and Foreign Trade or to contact the Jamaican High Commission in London to get assistance.

Rudd also told the MPs that the government was still checking to confirm no Windrush citizens had been wrongly deported, and had not yet begun to assess how many might have been detained over their supposed immigration status.

On Monday Ms Rudd unveiled an emergency package of measures in an attempt to draw a line under the affair, but the Home Office has remained under pressure as new cases continue to emerge.